Young death assemblages with limited time-averaging in rocky and Posidonia oceanica habitats in the Mediterranean Sea

Author(s)
Paolo G. Albano, Quan Hua, Darrell S. Kaufman, Martin Zuschin
Abstract

Death assemblages (DAs) are increasingly recognized as a valuable source to reconstruct past ecological baselines, due to the accumulation of skeletal material of non-contemporaneous cohorts. We here quantify the age and time-averaging of DAs on shallow subtidal (5–25 m) rocky substrates and in meadows of Posidonia oceanica in the eastern Mediterranean. We show that such DAs are very young – median ages 9–56 years – with limited time-averaging, one to two orders of magnitude less than on even nearby soft substrates. On rocky substrates, out-of-habitat transport is likely the main cause of loss of older shells. In Posidonia oceanica meadows, the root and rhizome system creates a dense structure – the matte – that quickly entangles and buries shells and limits the potential for bioturbation. The matte is, however, a peculiar feature of Posidonia oceanica, and age and time-averaging in meadows of other seagrass species may be different. The young age of DAs in these habitats requires a careful consideration of their appropriateness as baselines. The large difference in DA age between soft substrates, subject to numerous studies, and hard and seagrass substrates, rarely inspected with geochronological techniques, implies that DA dating is important for studies aiming at using DAs as baselines.

Organisation(s)
Department of Palaeontology
External organisation(s)
Stazione Zoologica Anton Dohrn, Australian Nuclear Science and Technology Organisation (ANSTO), Northern Arizona University
Journal
Geological Society, London, Special Publications
Volume
529
Pages
41-48
No. of pages
8
DOI
https://doi.org/10.1144/SP529-2022-224
Publication date
07-2023
Peer reviewed
Yes
Austrian Fields of Science 2012
105118 Palaeontology
ASJC Scopus subject areas
Water Science and Technology, Ocean Engineering, Geology
Portal url
https://ucrisportal.univie.ac.at/en/publications/7c5102e3-356e-4f46-b17d-df8b9d9b1039